Learning Horner's method Horner's method of polynomial

Reproduced in the blog:

Horner's method of polynomial

Is to simplify O (n ^ 2) is written to O (n) only.

However, this algorithm is also very friendly for polynomials.

 

. 1 #include <bits / STDC ++ H.>
 2  #define N 1001
 . 3  the using  namespace STD;
 . 4  int n-, X, A [N], MOD;
 . 5  int main ()
 . 6  {
 . 7    int ANS;
 . 8    Scanf ( " % D % D% D " , & n-, & x, & MOD); // n-represents the function f (x) the highest-order term of x, mod represents modulo number; 
. 9    for ( int I = 0 ; I <= n-; I ++ )
 10      Scanf ( " % D " , a & [I]); // a [I] represents a coefficient of each term; 
. 11    ANS =A [n-];
 12 is    for ( int I = N- . 1 ; I> = 0 ; i-- )
 13 is      {
 14        ANS = (X + A * ANS [I]) MOD%; // Horner's method body, equation It is f (x) = (... ( (a [n] * x + a [n-1]) * x + a [n-2]) * x + ... a [1]) * x + a [0]; 
15      }
 16    the printf ( " % D " , ANS);
 . 17    return  0 ;
 18 is }

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